Tips for Adding a Full Basement Modification

Posted by Dan Sater II on July 13, 2017

It is a clear trend. For the past 10 years, more and more people are asking to have stock plans modified. This is a great choice if you are looking for some very specific features in a home plan. However, there are some things to know before you request a quote to modify a plan.

Starting at the Bottom

One of the most common requests we get is to add a full basement to a plan. You might think that is an easy and fast modification. And in some cases it might be, but adding a full basement under a home can also be a very difficult and expensive modification.

Before you ask about adding a full basement, you need to look at the plan you are working with. If the plan comes standard with a slab foundation, there are going to be issues. This is because the plan in its original form has no floor structure. The floor structure of the home is the slab foundation. A home with a basement needs a wood structure to sit on top of the basement.

When a floor structure doesn’t exist, one must be created. This means calculating how the loads of the house structure are going to be supported by the flooring and then transferred down to the basement. It is not just a matter of simply designing and drawing the basement itself.

Besides designing and drawing the floor structure, you need to alter the original floor plan to create space for access to the basement. Somewhere in the plan, room needs to be made for a staircase. Usually this means sacrificing space from some other area of the home.

If giving up closet space, shifting rooms, or room lost in the garage is not acceptable, then the footprint of the plan will need to be expanded. Bumping out a wall or extending the length or width of a garage has a ripple effect. If the interior space of a plan is expanded this affects the exterior of the home. This will affect the elevations of the home, as well as the roof layout.

Simply adding a basement can in some instances cause as much as 30% of a plan to be redesigned and re-drawn. This can result in many hours of drafting time. The largest factor in any modification is the amount of drafting time it will take to complete.

What to Look For

Beyond finding a plan that comes with a full basement foundation, what can you do? The next best thing to a full basement is a crawl space foundation. This is because a crawl space foundation already has a fully designed and drawn floor structure.

The time and effort it takes to convert a crawl space foundation into a full basement is far less than when you start with a slab foundation. This means the modification will be less costly and quicker.

This of course will not solve the problem of finding room for a stairway. If the plan you like happens to be a two story plan, you are in luck. Usually very little modifications need to be made to a two story plan in order to add stairs down into a full basement.

The Bottom Line

If you can start with a plan that is as close to perfect (for you) as you can get before modifications are made, you will be in better shape. Selling stock home plans as a business only makes sense if the plans are sold in bulk. Meaning, in order for a plan to be profitable it needs to be sold many times. This is because it takes a lot of man-hours and design time to create a complete set of house plans. If turning a profit on the first sale of a home plan was required, you would not be able to purchase a home plan for under $15,000.00.

This needs to be kept in mind when you are thinking about modifying a home plan. What might sound like a simple task, adding a basement under a home, can be quite time consuming. If the list of modifications is too long, the cost to make the changes will exceed the cost of the stock plan. It can even approach the cost of the initial development of the plan.

It all goes back to communication and compromise. Make sure you talk with your builder to see if there are any issues with your location when it comes to adding a full basement. Make sure you talk to your partner about the need for a basement and what you might need to alter or sacrifice for it. Then you need to carefully study the home plan you like to see if adding a basement is going to be complicated.

If you have any questions about any of our plans, please give us a call. We do have a procedure for requesting a modification quote. If you give us a call we can’t tell you right away what the cost will be. We can, however, let you know if what you are thinking is going to be possible with the plan you are considering. We can also help you find a plan that might work best in your situation.